What do you mean you have to recalibrate the compass? Is there an error it is giving? Or is just north up and then switches direction on you when you change position as there is a setting to keep north locked and unlocked if I remember correctly. I'll try to help as much as I can as I have the same unit and haven't had too many issues.
I will say that the tech forums on Delorme have some knowledgeable folks that will work with you if you ask politely and will walk you through and help troubleshoot.